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Lecture 1: Forensic Biology: A Sub-discipline of Forensic Science.

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Presentation on theme: "Lecture 1: Forensic Biology: A Sub-discipline of Forensic Science."— Presentation transcript:

1 Lecture 1: Forensic Biology: A Sub-discipline of Forensic Science

2  About your professor  Class and Individual characteristics  About this course  Creating a Crime Map  What is forensic science?  Forensic laboratory services  What is forensic biology?  History of forensic biology: 1960-present 2

3 Name: Ballard, Ruth Hair: Brown Eyes: Green Ht: 5’ 2” Wt: 105 Occupation: Professor and researcher Last Known Address: Dept of Biological Sciences California State University, Sacramento

4 4 Class Characteristic: Often covered in white fur

5 5 Identifying Characteristic: DNA profile

6 6 DNA breakthroughs in 1990s + News coverage = BIO 150 Naïve new professor Students watching TV shows + TV shows + +

7  A Crime Map is a visual summary of a crime  Becomes a tool for remembering how everything fits together  Helps put biological evidence in context as you receive it  Can be organized in many different ways  This is your opportunity to be creative! ▪ Colored pencils, flow charts, time-lines  Submit one per lab pair 7

8  At a minimum should include: Basic information about the crime ▪ Date, time, location ▪ Victims ▪ Suspect (if identified) ▪ Eyewitness reports (to establish probable scenarios)  Evidence collected ▪ When/where/by whom ▪ Where it is being stored  Pending or completed analyses by other units  What’s available for testing and what’s missing 8

9  Example on the board  You can continue to update your crime map as the semester progresses  Add results of your own lab analyses  Due for grading in lab on week from this coming Friday  This week in lab: Introduction  Next week in lab: Lab 1 (The Crime Scene: Setting, Evidence, and Process); Crime map due  Use supplementary materials at back of lab manual as your source of information for the map 9

10  Forensic Science is the application of science to matters of Law.  Is uniquely cross-disciplinary and draws upon:  Chemistry (Is this white power cocaine?)  Biology (Did the semen come from the suspect?)  Physics (How fast was the car going at impact?)  Anthropology (Are these bones human?)  Medicine (How did this child die?) 10

11  “Matters of Law” include:  Crimes ▪ Homicide, sexual assault, burglary, etc.  Disputes among individuals ▪ Wrongful death, patents, etc.  Establishing rights ▪ Parentage; immigration, land disputes  Investigation of disasters ▪ Natural and man-made 11

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14 'Baby 81' Reunited With Parents After DNA Tests End Agonizing Post-Tsunami Custody Dispute

15 DNA Science Matches Crash Victims With Families By MATTHEW PURDY Published: November 30, 1996

16  Unique roles of forensic scientists:  Assist in recognition and collection of physical evidence  Document and maintain chain-of-custody  Analyze and evaluate the evidence using a variety of scientific approaches  Interact with the legal system ▪ Assist attorneys (and often law enforcement personnel) ▪ Testify in Court 16

17 17 Typical U.S. courtroom. Where does everyone sit?

18  NOT a branch of Law Enforcement!  Forensic scientists do not interrogate and arrest suspects  Forensic scientists do not usually investigate crimes ▪ Crime Scene units of law enforcement agencies and forensic medical professionals collect most of the evidence ▪ Evidence from the crime scene is then sent to forensic scientists at crime labs for analysis 18

19 19 Lab Director Administration BiologyCriminalisticsChemistryToxicologyQuality Assurance Comparative Evidence Trace Evidence Arson Controlled Substances Clandestine Labs Toxicology Alcohol Also see Table 1.1 in textbook

20  Most crime labs in U.S. are public sector laboratories available only to law enforcement and prosecutors  30 public crime labs  11 California Department of Justice  9 County Sheriff’s Crime Labs  7 City Police Department Crime Labs  3 County District Attorney Crime Labs 20

21  California Dept of Justice crime labs:  Sacramento  Ripon  Watsonville  Richmond (does the most hiring in California)  Santa Barbara  Chico  Fresno  Riverside  Santa Rosa  Eureka  Redding 21

22  County Sheriff’s Dept crime labs in California:  Alameda County (San Leandro)  Fresno County (Fresno)  Contra Costa County (Martinez)  Los Angeles County (Los Angeles)  Orange County (Santa Ana)  San Bernardino County (Rancho Cucamonga)  San Mateo County (San Mateo)  San Diego County (San Diego)  Ventura County (Ventura) 22

23  County District Attorney crime labs in California:  Sacramento County (Sacramento)  Kern County (Bakersfield)  Santa Clara County (San Jose) 23

24  City Police Dept crime labs in California:  El Cajon  Los Angeles  San Francisco  Huntington Beach  Oakland  Long Beach  San Diego 24

25  There are also private forensic laboratories  Independently test forensic evidence  Available to defense attorneys and their clients as well as the general public  16 private labs in California including  SERI (Richmond CA)  Forensic Analytical (Hayward CA)  Forensic Laboratory Services (San Luis Obispo)  Forensic DNA Consulting (Mountain View) 25

26 26 Current Model: Crime Lab Crime Scene Prosecution Defense Courts

27 27 Ideal Model: Crime Lab Crime Scene Prosecution Defense COURT

28 28 Gas chromatography-mass spectrometer Which unit of a crime lab would have this?

29 29 Capillary electrophoresis unit for Forensic DNA profiling Which unit of a crime lab would have this?

30 30 Tissue samples from a deceased person, suspect, or crime victim. Which unit of a crime lab would process these and for what purpose?

31 31 A comparison microscope for ballistic analysis. Which unit of a crime lab would have this?

32 32 Scanning electron microscope used in gunshot residue analysis. Which unit of a crime lab would have this?

33  Broad Definition: The application of the theory and practice of any branch of the biological sciences to matters of law  Pathology (anatomy and physiology)  Entomology (invertebrate zoology; insects)  Odontology (dentistry)  Physical anthropology (study of bones)  Microbiology, botany, wildlife…  Body fluids (serology) and DNA 33

34  Forensic Pathology  Autopsies used to determine: ▪ Cause of death ▪ Manner of death: ▪ Natural ▪ Homicide ▪ Suicide ▪ Accident ▪ Undetermined 34

35 35 Forensic Pathology Facility. Run by Coroner’s or Medical Examiner’s Office

36  Forensic Entomology  The study of insects in relation to a criminal investigation  Estimating time of death ▪ Stages of insect development 36 After death, blow flies infest dead bodies

37  Forensic Odontology  Use characteristics of teeth, alignment, and overall structure  Bite mark analysis  Useful in the identification of victims whose bodies are unrecognizable  Most people have dental records  Dentition and dental history are unique to each person 37

38  Forensic Microbiology  Forensic Botany  Forensic Wildlife 38

39  Narrow Definition: The application of serological and DNA testing in matters of Law.  Goal is to generate identifying information from biological evidence: DNA  Forensic serology ▪ Finding/identifying biological stains and materials  Forensic DNA analysis ▪ Generating DNA profiles from biological stains/materials 39

40  DNA used to:  Link suspect to crime scene  Link victim to crime scene  Link suspect to victim  Link victim to suspect  Link multiple crimes to a single suspect  We’ll learn more about how cells (and DNA) are transferred in Lecture 2 40

41  Two trends:  Dramatically increased level of probability that a suspect is the source of a crime scene sample (16 orders of magnitude)  Dramatically fewer numbers of cells need for testing ▪ Ability to generated DNA profiles from “trace evidence,” including “contact DNA” 41

42  Random match probability = RMP  Probability of randomly selecting an individual from the population with the same combination of biological markers as the evidence sample  Power of discrimination = PD = 1/RMP 42

43  Began with discovery of red blood cell surface antigen polymorphisms  1900 Karl Landsteiner discovered ABO blood group antigens  Developed by Lattes into ABO blood typing  Immediate applications in medicine (transfusions)  First applied to forensic casework in 1960s 43

44  Limitations:  Not very sensitive (lots of cells needed)  Sample must be fresh  Non-secretors  RMP high; PD low ▪ 49% of Americans have blood type O ▪ RMP ~ 0.25 (1 in 4); DP = 4 44

45  Blood protein markers  By 1980 approximately 100 had been discovered  Several used by forensic biologists  Combined with ABO antigen system ▪ RMP ~0.001(1 in 1000) ▪ PD = 1000  Same limitations as the ABO system but higher PD 45

46  DNA Fingerprinting  1984  Sir Alec Jeffreys ▪ Used in 1986 to solve murder case in the United Kingdom (The Blooding)  High PD (~10 9 )  Still required a large, fresh sample  Large visible blood stain  Rape with ejaculation taken soon after crime 46

47  Huge breakthrough in 1986: PCR  Polymerase chain reaction  Allowed “amplification” of low-level DNA prior to analysis  A hundred cells rather than hundreds of thousands ▪ Human cell contains 6 pg DNA ▪ DNA fingerprinting: 1 ug needed = 167,000 cells ▪ PCR: 100 pg needed = 17 cells 47

48 Size of blood stain needed for DNA Fingerprinting Size of blood stain needed for PCR

49 49 trace levels = Identity assumed Blood antigens/proteins ( ) Progress of Forensic Biology 1960-Present DNA fingerprinting ( ) STR typing (2000-present) DQA1-PM ( )


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